Ethyl-activated carbon nitride for efficient photocatalytic CO2 conversion

Surface functional groups of photocatalysts play a key role in the transfer of photogenerated carriers and the active site of the reaction, which severely influence the photocatalytic conversion process. Therefore, reasonable and accurate regulation of surface groups can greatly optimize photocatalytic performance. Herein, we performed optimization on the unpolymerized NH2 group of carbon nitride (g-C3N4) by introducing an ethyl group with a strong electron-donating ability to obtain the E-CN photocatalysts. X-ray photoelectron spectroscopy confirmed the successful embedding of the ethyl group. Time-resolved spectroscopy and density function theory calculations verified that the photogenerated carrier changes in a favorable direction. Finally, the Gibbs free energy showed that E-CN significantly decreases the energy barrier of CO2 conversion to *COOH. The results revealed that the conversion rate of CO2 to CO is 47.08 µmol g−1 h−1. This work offers a reliable reference to improve the performance of photocatalysts by optimizing their surface functional groups.